Numerical study on diffusion field as affected by arrangement of supply and exhaust openings in conventional flow type clean room

Abstract

Room air distribution is greatly affected by the arrangement of supply outlets and, possible, exhaust inlets. The influence of those arrangements on the flow fields is studied here by numerical simulation based on the {kappa}-{epsilon} two-equation turbulence model. Room air flows in several types of conventional-flow-type clean rooms are analyzed from this point of view. The flow fields in such rooms as analyzed her are well modeled as serial combinations of flow units, each of which is composed of one supply jet and the rising streams around it. When the number of supply outlets is decreased, the flow units corresponding to the eliminated supply outlets vanish and the remaining flow units expand. A change in arrangement or in the number of exhaust inlets hardly affects the entire flow field; however, such changes often has a large influence on the contaminant diffusion field.